Scientists want to raise extinct species from the dead

It's called "de-extinction": the notion that we can revive extinct species that for some reason or another -- usually human intervention -- have disappeared from the world. Twenty years ago, the idea hit the mainstream when Michael Crichton's Jurassic Park was made into a film; 10 years ago, the first extinct animal was resurrected, a clone of a Pyrenean Ibex. Revived by scientists at the Centre of Food Technology and Research of Aragon, Zaragoza, in northern Spain, and the National Research Institute of Agriculture and Food, Madrid, Spain, the hapless creature was a victim of crude technology, expiring just moments after birth.

But over the years, cloning technology has grown more precise, to the point where at least one program is underway to clone endangered animals -- a move that could have a number of benefits, including increasing the population overall, and allowing researchers to leave wild animals undisturbed in their natural habitats.

And, as it turns out, there are many reasons. What do you want to clone it for? Where will it live? How will it live? How will you ensure enough genetic variation for it to be able to create a new population? And, not least, which animals will you clone?

It's not as simple as just picking up a bit of dinosaur DNA from a mosquito trapped in amber; the number of viable samples in the world is very small. Dinosaur DNA is, in fact, too old and degraded to be of any use.

Revive and Restore, an organisation committed to bringing extinct species back into the world, has created a list of viable species. It contains 24 animals and one plant, and has selected them based on desirability, including such factors as how important its ecological role was, and whether the genome is small enough to be managed.

But then you run into ethical concerns. How did the animal become extinct? Was it a natural process? Will we damage the ecosystem by reversing that extinction?

Although de-extinction projects are already underway -- in January, scientists led by Dr Michael Archer at the University of New South Wales briefly managed to revive an extinct frog -- most agree that many of these questions need to be properly answered before cloning projects can commence.

But imagine the wonder of taking yourself to a de-extinction zoo and seeing up close a real live Tasmanian tiger or woolly mammoth. That would be quite an experience, indeed.